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1.
The aim of this study was to determine the immunohistochemical expression and localization of insulin-like growth factor-I (IGF-I), transforming growth factor-β2 (TGF-β2), basic fibroblast growth factor (bFGF) and epidermal growth factor-receptor (EGF-R) in developing rat ovaries.Eighteen female Wistar rats were enrolled in this study; newborn (n = 6), one-month-old (n = 6) and adult (n = 6) rats. Formalin-fixed and parafin-embedded ovarian tissues were stained with antibodies against IGF-I, TGF-β2, bFGF and EGF-R, immunohistochemically. The ovarian cells were evaluated by semi-quantitative scoring system under light microscope.The staining of IGF-I, TGF-β2, bFGF and EGF-R were most intense in the oocytes and were heavily at one-month-old rats. A moderate immunostaining in theca cells and corpus luteii reacted with IGF-I in adult rats. Furthermore the staining intensity for IGF-I was moderate in granulosa cells of newborn rat ovaries. We detected also a moderate staining for TGF-β2 in corpus luteii of adult rats. In addition, we found a bFGF immunostaining mainly in oocytes of follicles of young and adult rats. Immunostaining for EGF-R was moderate in granulosa cells of one-month-old rats.In conclusion, this study suggests that growth factors play a pivotal role in ovarian function, especially in follicular development. The role of growth factor in controlling degeneration or growth (or both) of ovary follicles remain as explained. 相似文献
2.
Simon P. Robinson William C. Rose AnnaMaria Casazza 《The Journal of steroid biochemistry and molecular biology》1990,37(6)
The influence of modulating circulating levels of epidermal growth factor (EGF) and transforming growth factor β1 (TGF-β1) on tumorgrowth was examined in a variety of mouse models. Removal of the EGF-rich submandibular gland from host mice failed to alter the growth of a variety of human tumor xenografts or a C3H mouse tumor. Infusion of EGF from Alzet minipumps raised circulating EGF levels. However, only the A549 human tumor xenograft showed any significant increase in growth in the presence of EGF infusion and this response was marginal. The growth of Wehi 3BD+ and A549 tumor lines in culture was inhibited by TGF-β1. The growth of these lines in vivo, however, was not significantly altered by the administration of TGF-β1 via a variety of routes. 相似文献
3.
Recent evidence has implicated cytokines and growth factors in the initiation of parturition in women. In the present study, the amnion-derived cell line WISH was used to determine whether proinflammatory cytokines (interleukins 1β, 6, and 8, tumor necrosis factor-α, and granulocyte/macrophage colony stimulating factor) could amplify epidermal growth factor-induced prostaglandin E2 production. WISH cells were preincubated with cytokines (0.0001–10 ng/ml) for 60 min and then challenged with EGF (10 ng/ml) for 4 hrs after which PGE2 production was measured by radioimmunoassay. EGF, IL-1β and TNF-α alone caused a dose-dependent increase in PGE2 production, while IL-6, IL-8 and GM-CSF were ineffective over the dose range tested. When cells were preincubated with IL-1β or TNF-α, there was a dose-dependent potentiation of EGF-induced PGE2 production that was greater than the sum of EGF alone and IL-1β or TNF-α alone. In each case, the minimum dose of IL-1β or TNF-α which amplified EGF-induced PGE2 production was 0.1 ng/ml (p < 0.05, Student's t-test). These data show that low concentrations of IL-1β or TNF-α may serve to amplify EGF-mediated PGE2 biosynthesis in amnion-derived cells and suggest that cytokines may modulate EGF function in responsivecells. 相似文献
4.
Interleukin-1 (IL-1) plays an important role in cartilage destruction associated with inflammatory and degenerative arthritis because of its ability to induce matrix degrading enzymes. Previously, we have shown that the IL-1-induced chondrocyte protease activity was inhibited by transforming growth factor-β (TGF-β). In this paper, we show that TGF-β inhibits the IL-1-induced synthesis of collagenase and stromelysin by reducing the steady-state mRNA levels in rabbit articular chondrocytes. We further demonstrate that TGF-β-treated chondrocytes show reduced 125I-IL-1 binding that returns to a normal level when TGF-β is removed from the culture medium. The inhibitory effect of TGF-β is observed for both naturally occurring as well as fibroblast growth factor (FGF)-inducible binding sites (receptors). Scatchard analysis of receptor—ligand interactions demonstrate that the reduced binding is due to a reduction in the number of receptors for IL-1 and is not due to changes in affinity. Affinity cross-linking studies suggest that control chondrocytes contain two major cross-linked bands of Mr =116 and 80 kDa and a minor band of Mr =100 kDa. FGF-treated cells show enhanced levels of all the bands, plus an additional 200-kDa band. TGF-β treatment of chondrocytes results in the reduction of all of these bands in both control as well as FGF-induced cells. These observations suggest that the ability of TGF-β to down-regulate the IL-1 receptor may be a mechanism by which it exerts its effects in antagonizing the IL-1 activity on chondrocytes. 相似文献
5.
Platelet-derived growth factor (PDGF), epidermal growth factor (EGF), insulin-like growth factor-I (IGF-I), and transforming growth factor-β (TGF-β) are potent mitogens present in human platelets. Since they are likely to be released simultaneously at the site of vessel injury, their combined effects on vascular smooth muscle cells are more relevant physiologically than their individual actions. Therefore, we added various concentrations of growth factors to quiescent porcine aortic smooth muscle cells cultured in lowserum (0.5%) medium and measured the amount of [3H]thymidine incorporated into DNA. Effect of TGF-β alone was concentration-dependent: stimulatory (1.5-fold increase over the basal) at 0.025 ng/ml and inhibitory at 0.1 ng/ml. Effects of the other three growth factors on DNA synthesis were only stimulatory; their maximally effective concentrations were 20 ng/ml for PDGF (eightfold over the basal), 40 ng/ml for EGF (sixfold increase), and 20 ng/ml for IGF-I (fourfold increase). When PDGF, EGF, and IGF-I were added at submaximally effective concentrations, their effects were additive. TGF-β at 1 ng/ml inhibited at least 50% of the effects of 20 ng/ml EGF and of 10 ng/ml IGF-I, whereas inhibition of the effect of 10 ng/ml PDGF required 10 ng/ml of TGF-β. The concentration of TGF-β needed to inhibit 50% of the combined effect of EGF, IGF-1, and PDGF was 5 ng/ml. These results show complex interrelationships between the growth factors contained in the α-granules of human platelets in their effects on porcine aortic smooth muscle cells. 相似文献
6.
Anton Scott Goustin Greg A. Nuttall Edward B. Leof Gouri Ranganathan Harold L. Moses 《Experimental cell research》1987,172(2)
Transforming growth factor type β (TGFβ) is a pleiotropic regulator of cell growth with specific high-affinity cell-surface receptors on a large number of cells; its mechanism of action, however, is poorly defined. In this report, we utilized the mouse fibroblast line AKR-2B to explore the question of the temporal requirements during the cell cycle in regard to both the growth inhibitory and the growth stimulatory action of TGFβ. The results indicate that AKR-2B cells are most sensitive to the inhibitory action of TGFβ during early to mid-G1. In addition, TGFβ need be present only briefly (as little as l min) in order to exert its inhibitory effect on EGF-induced DNA synthesis. Likewise, the stimulatory effect of TGFβ in the absence of EGF requires only an equally brief exposure to TGFβ. Use of homogeneous 125I-labeled TGFβ in a cell-binding assay demonstrates that TGFβ bound to cell-surface receptors can readily exchange into the culture medium T1/2 = 120 min), helping to rule out the possibility that persistent receptor-bound TGFβ is the source of a continuous stimulus. The data indicate that TGFβ exposure induces a stable state in the cell (T1/2 = 20 h) similar to but distinct from the state of “competence” induced by platelet-derived growth factor (PDGF). 相似文献
7.
C. M. M. van der Kruijssen A. Feijen D. Huylebroeck A. J. M. van den Eijnden-van Raaij 《Experimental cell research》1993,207(2)
Activins are potentially important regulators of early developmental processes in vertebrates. Although the different forms of activin appear to be differentially expressed during early amphibian, avian, and murine development, little is known about the factors that regulate their expression. In this study we report the qualitative effects of several growth and differentiation factors on the expression of inhibin subunits in three differentiated cell lines derived from P19 embryonal carcinoma cells. These cell lines include mesodermal (MES-1), neuroepithelial (EPI-7), and visceral endoderm-like (END-2) cell types, expressing both inhibin βA and βB subunit mRNAs. We have shown for the first time that this expression is modulated by transforming growth factor (TGF)β1 and TGFβ2 but not significantly by other growth factors such as leukemia inhibitory factor or members of the fibroblast growth factor family (aFGF, bFGF, or kFGF). βA mRNA expression is increased while βB expression is simultaneously decreased by TGFβ. Furthermore, TGFβ increased the amount of bioactive activin secreted by MES-1 and END-2 cells. Inhibin α subunit mRNA expression is not affected by TGFβ. These results point to a possible role of type β transforming growth factors as regulators of activin expression in embryonal cells. 相似文献
8.
Naseema M. Hoosein Mary K. McKnight Alan E. Levine Kathleen M. Mulder Karla E. Childress Diane E. Brattain Michael G. Brattain 《Experimental cell research》1989,181(2)
In this study we have employed a model system comprising three groups of colon carcinoma cell lines to examine the growth-inhibitory effects of two molecular forms of transforming growth factor-β (TGF-β), TGF-β1 and TGF-β2. Aggressive, poorly differentiated colon carcinoma cells of group I did not respond to growth inhibitory effects of TGF-β1 or TGF-β2, while less aggressive, well-differentiated cells of group III displayed marked sensitivity to both TGF-β1 and TGF-β2 in monolayer culture as well as in soft agarose. One moderately well-differentiated cell line from group II which has intermediate growth characteristics failed to respond to TGF-β1 or TGF-β2, but the growth of two other cell lines in this group was inhibited. TGF-β1 and TGF-β2 were equally potent, 50% growth inhibition for responsive cell lines being observed at a concentration of 1 ng/ml (40 pM). Antiproliferative effects of TGF-β1 and TGF-β2 in responsive cell lines of groups II and III were associated with morphological alterations and enhanced, concentration-dependent secretion of carcinoembryonic antigen. Radiolabeled TGF-β1 bound to all three groups of colon carcinoma cells with high affinity (Kd between 42 and 64 pM). These data indicate for the first time a strong correlation between the degree of differentiation of colon carcinoma cell lines and sensitivity to the antiproliferative and differentiation-promoting effects of TGF-β1 and TGF-β2. 相似文献
9.
Elisa Migliorini Dhruv Thakar Jens Kühnle Rabia Sadir Douglas P. Dyer Yong Li Changye Sun Brian F. Volkman Tracy M. Handel Liliane Coche-Guerente David G. Fernig Hugues Lortat-Jacob Ralf P. Richter 《Open biology》2015,5(8)
The glycosaminoglycan heparan sulfate (HS), present at the surface of most cells and ubiquitous in extracellular matrix, binds many soluble extracellular signalling molecules such as chemokines and growth factors, and regulates their transport and effector functions. It is, however, unknown whether upon binding HS these proteins can affect the long-range structure of HS. To test this idea, we interrogated a supramolecular model system, in which HS chains grafted to streptavidin-functionalized oligoethylene glycol monolayers or supported lipid bilayers mimic the HS-rich pericellular or extracellular matrix, with the biophysical techniques quartz crystal microbalance (QCM-D) and fluorescence recovery after photobleaching (FRAP). We were able to control and characterize the supramolecular presentation of HS chains—their local density, orientation, conformation and lateral mobility—and their interaction with proteins. The chemokine CXCL12α (or SDF-1α) rigidified the HS film, and this effect was due to protein-mediated cross-linking of HS chains. Complementary measurements with CXCL12α mutants and the CXCL12γ isoform provided insight into the molecular mechanism underlying cross-linking. Fibroblast growth factor 2 (FGF-2), which has three HS binding sites, was also found to cross-link HS, but FGF-9, which has just one binding site, did not. Based on these data, we propose that the ability to cross-link HS is a generic feature of many cytokines and growth factors, which depends on the architecture of their HS binding sites. The ability to change matrix organization and physico-chemical properties (e.g. permeability and rigidification) implies that the functions of cytokines and growth factors may not simply be confined to the activation of cognate cellular receptors. 相似文献
10.
Summary Bothras and the transplasma membrane electron transport system have been implicated in the control of cell growth. Since the loss of growth regulation is at the heart of the cancerous phenotype, we have investigated the effect of factors like antitumor drugs, which inhibit cell growth, and growth factors which either cause or prepare the cells for growth. We have found that growth factors increase the plasma membrane electron transport of the normal cells but not that of the cells which have been transfected with oncogenicras (which have a 2–5-fold faster basal rate). In the presence of adriamycin the activity of the electron transport system is and cell numbers are decreased more in normal cells than in the cells which have been transfected with the oncogenic version of the Harveyras gene. Cisplatin inhibits cell growth but does not inhibit ferricyanide reduction. Ferricyanide alone or in conjunction with EGF or TPA does not stimulate cell proliferation with either cell line in the absence of fetal calf serum, so simple activation of plasma membrane electron transport is not sufficient to activate a complete growth response.Abbreviations EGF
epidermal growth factor
- TPA
phorbol myristate acetate
- PDGF
platelet derived growth factor
- MTT
3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromides
- SDS
sodium dodecyl sulfate 相似文献
11.
Gerry T. Snoek Cees H. Koster Siegfried W. de Laat Martin Heideveld Antony J. Durston Everardus J. J. van Zoelen 《Experimental cell research》1990,187(2)
The Xenopus laevis XTC cell line has been analyzed for the production of polypeptide growth factors and mesoderm-inducing activity. By the use of specific biological assays, it is shown that XTC cells produce a growth factor functionally related to the platelet-derived growth factor (PDGF) and two transforming growth factor (TGF)β-like activities. Mesoderm-inducing activity, as measured on X. laevis ectodermal explants from stage 10 embryos, was found to coelute on a Bio-Gel P-100 column with one of the TGFβ-like activities at an apparent molecular weight of 6–10 kDa. Analysis of the DNA content from XTC cells by flow cytometry demonstrated that the cell line is heterogeneous and consists of both tetraploid and diploid cells. Cloning of the XTC cells and selecting single-cell colonies on the basis of their ability to grow in soft agar resulted in the isolation of several homogeneous, morphologically different clonal derivatives. Analysis of conditioned medium from these clonal derivatives showed that only one of them, the only diploid line among six investigated, produced a strong heat- and acid-stable mesoderm-inducing activity that induced notochord and muscle formation in stage 10 X. laevis ectodermal expiants. The relation between this activity and a recently described TGFβ-like mesoderm-inducing factor obtained from XTC-conditioned medium will be discussed. In conclusion, a clonal cell line derived from X. laevis XTC cells which provides a good source for further characterization of mesoderm-inducing factors has been established. 相似文献
12.
Yu Hou ZeBin Mao XueLei Wei Lin Lin LianXu Chen HaiJun Wang Xin Fu JiYing Zhang Changlong Yu 《Matrix biology》2009,28(6):324-335
Repaired Achilles tendons typically take weeks before they are strong enough to handle physiological loads. Gene therapy is a promising treatment for Achilles tendon defects. The aim of the present study was to evaluate the histological/biomechanical effects of Transforming growth factor-β1 (TGF-β1) and vascular endothelial growth factor 165 (VEGF165) gene transfer on Achilles tendon healing in rabbits. Bone Marrow-Derived Mesenchymal Stem Cells (BMSCs) were transduced with adenovirus carrying human TGF-β1 cDNA (Ad-TGF-β1), human VEGF165 cDNA (Ad-VEGF165), or both (PIRES-TGF-β1/VEGF165) Viruses, no cDNA (Ad-GFP), and the BMSCs without gene transfer and the intact tendon were used as control. BMSCs were surgically implanted into the experimentally injured Achilles tendons. TGF-β1 distribution, cellularity, nuclear aspect ratio, nuclear orientation angle, vascular number, collagen synthesis, and biomechanical features were measured at 1, 2, 4, and 8 weeks after surgery. The TGF-β1 and TGFβ1/VEGF165 co-expression groups exhibited improved parameters compared with other groups, while the VEGF165 expression group had a negative impact. In the co-expression group, the angiogenesis effects of VEGF165 were diminished by TGF-β1, while the collagen synthesis effects of TGF-β1 were unaltered by VEGF165. Thus treatment with TGF-β1 cDNA-transduced BMSCs grafts is a promising therapy for acceleration and improvement of tendon healing, leading to quicker recovery and improved biomechanical properties of Achilles tendons. 相似文献
13.
Even though few steroids are used for the treatment of leukemia, 2β-(4-methylpiperazinyl)-5α-androstane-3α,17β-diol (1) was recently reported for its ability to inhibit the proliferation of human leukemia HL-60 cells. With an efficient procedure that we had developed for the aminolysis of hindered steroidal epoxides, we synthesized a series of 2β-amino-5α-androstane-3α,17β-diol N-derivatives structurally similar to 1. Hence, the opening of 2,3α-epoxy-5α-androstan-17β-diol with primary and secondary amines allowed the synthesis of aminosteroids with diverse length, ramification, and functionalization of the 2β-side chain. Sixty-four steroid derivatives were tested for their capacity to inhibit the proliferation of HL-60 cells; thus obtaining first structure–activity relationship results. Ten aminosteroids with long alkyl chains (7–16 carbons) or bulky groups (diphenyl or adamantyl) have shown antiproliferative activity over 78% at 10 μM and superior to that of the lead compound. The 3,3-diphenylpropylamino, 4-nonylpiperazinyl and octylamino derivatives of 5α-androstane-3α,17β-diol inhibited the HL-60 cell growth with IC50 of 3.1, 4.2 and 6.4 μM, respectively. They were also found to induce the HL-60 cell differentiation. 相似文献
14.
Ron Saulnier Bhavna Bhardwaj Jennifer Klassen Doris Leopold Nader Rahimi Eric Tremblay Deane Mosher Bruce Elliott 《Experimental cell research》1996,222(2):360
Stromal cells are important regulators of mammary carcinoma growth and metastasis. We have previously shown that a 3T3-L1 adipocyte cell line secretes hepatocyte growth factor (HGF), which stimulates proliferation of a murine mammary carcinoma (SP1) in monolayer cultures (DNA Cell Biol.13, 1189–1897, 1994). We now examine the role of growth factors and the extracellular matrix protein fibronectin in stimulation of anchorage-independent growth of SP1 cells. Purified transforming growth factor-β (TGF-β) stimulated significant colony growth in soft agar cultures, whereas HGF had a lesser effect. Analysis by confocal microscopy revealed that carcinoma cell colonies contained extracellular microfibrils composed of fibronectin. Partial depletion of fibronectin from 7% FBS/agar cultures reduced the number of colonies; colony growth could be recovered by adding back exogenous fibronectin. Addition of the 70-kDa N-terminal fragment of fibronectin, which inhibits fibronectin fibril formation, reduced growth of SP1 cell colonies, but an 85-kDa fragment containing the cell binding domain did not inhibit colony growth. These findings indicate that deposition of extracellular fibronectin fibrils is necessary, but not sufficient, for anchorage-independent growth of SP1 mammary carcinoma cells; growth factors are also required. SP1 cells had less fibronectin mRNA and secreted less fibronectin protein under anchorage-independent conditions than under anchorage-dependent conditions, as determined by Northern blotting and immunoprecipitation analysis. Thus, both growth factors (HGF and TGF-β) and fibronectin may be important regulators of paracrine stimulation by stromal cells of anchorage-independent growth of mammary carcinoma cells. 相似文献
15.
Beginning with the observation that hepatocyte growth factor (HGF) induces the formation of branching tubular structures in Madin-Darby canine kidney (MDCK) cells cultured in Type I collagen gels but not in basement membrane Matrigel, we examined the individual components within this complex basement membrane extract to determine the effect of these proteins on the morphogenetic changes mediated by HGF. After extraction of several growth factors from Matrigel, HGF was still unable to induce process formation, an early event in tubulogenesis, indicating that one or more of the remaining extracellular matrix (ECM) proteins or growth factors were exerting the inhibitory effect. By individually adding back these components to MDCK cells grown in Type I collagen gels in the presence of HGF, we were able to establish that: (1) certain ECM proteins, such as laminin, entactin, and fibronectln, actually facilitated the formation of branching tubular structures and increased their complexity; (2) other ECM proteins, such as Type IV collagen, heparan sulfate proteoglycan, and vitronectin, caused marked inhibition of HGF-induced morphogenesis; and (3) not only did transforming growth factor-β (TGF-β) inhibit the formation of tubular structures, but those which did form exhibited little branching, thereby suggesting that TGF-β modulates tubulogenesis as well as branching. These results suggest that a tubulogenic morphogen such as HGF and a tubulogenesis-inhibitory morphogen such as TGF-β can, in the context of the dynamic matrix known to exist during epithelial tissue development, modulate the degree of tubule (or ductal) formation, the length of these tubules, and the extent of their arborization. The relevance of these findings to tubulogenesis and branching during kidney development is discussed. 相似文献
16.
Fortunato Ciardiello Nancy Hynes Nancy Kim Eva M. Valverius Marc E. Lippman David S. Salomon 《FEBS letters》1989,250(2)
An enhanced expression of transforming growth factor-α (TGFα) was demonstrated in two clones of NOG-8 mouse mammary epithelial cells, NOG-8 SR1 and NOG-8 SR2, that have been transformed by a v-Ha-ras oncogene. The amount of TGFα production in NOG-8 SR1 and NOG-8 SR2 cells was dependent on the level of p21ras expression in these clones, which directly correlated with their cloning efficiency in soft agar. There was also a decrease in the number of epidermal growth factor (EGF) receptors on the NOG-8 SR1 and NOG-8 SR2 cells that is proportional to the amount of TGFα secreted. These effects were specific for ras because neu-transformed NOG-8 cells grew in soft agar at a comparable level to NOG-8 SR2 cells yet did not show any increase in TGFα production or change in EGF receptor expression. 相似文献
17.
Kazuhisa Nozawa Maki Fujishiro Mikiko Kawasaki Hiroshi Kaneko Kazuhisa Iwabuchi Mitsuaki Yanagida Fujihiko Suzuki Keiji Miyazawa Yoshinari Takasaki Hideoki Ogawa Kenji Takamori Iwao Sekigawa 《Arthritis research & therapy》2009,11(6):R174
Introduction
A protein analysis using a mass spectrometry indicated that there are serum proteins showing significant quantitative changes after the administration of infliximab. Among them, connective tissue growth factor (CTGF) seems to be related to the pathogenesis of rheumatoid arthritis (RA). Therefore, this study was conducted to investigate how CTGF is associated with the disease progression of RA.Methods
Serum samples were collected from RA patients in active or inactive disease stages, and before or after treatments with infliximab. CTGF production was evaluated by ELISA, RT-PCR, indirect immunofluorescence microscopy, and immunoblotting. Osteoclastogenesis was evaluated using tartrate-resistant acid phosphatase (TRAP) staining, a bone resorption assay and osteoclasts specific catalytic enzymes productions.Results
The serum concentrations of CTGF in RA were greater than in normal healthy controls and disease controls. Interestingly, those were significantly higher in active RA patients compared to inactive RA patients. Furthermore, the CTGF levels significantly were decreased by infliximab concomitant with the disease amelioration. In addition, tumour necrosis factor (TNF)α can induce the CTGF production from synovial fibroblasts even though TNFα can oppositely inhibit the production of CTGF from chondrocytes. CTGF promoted the induction of the quantitative and qualitative activities of osteoclasts in combination with M-CSF and receptor activator of NF-κB ligand (RANKL). In addition, we newly found integrin αVβ3 on the osteoclasts as a CTGF receptor.Conclusions
These results indicate that aberrant CTGF production induced by TNFα plays a central role for the abnormal osteoclastic activation in RA patients. Restoration of aberrant CTGF production may contribute to the inhibition of articular destruction in infliximab treatment. 相似文献18.
Chiarella Bozzo Giorgio Bellomo Lorenzo Silengo Guido Tarone Fiorella Altruda 《Experimental cell research》1997,237(2):326
We have investigated the role of extracellular matrix (ECM) and growth factors in the survival of nonadherent human neuroblastoma cells (line SK-N-BE). Cells cultured in serum-free medium under nonadherent conditions died with apoptotic-like features (cromatin condensation and nuclear fragmentation). SK-N-BE cells underwent neuronal differentiation in response to retinoic acid (RA). While RA itself did not induce apoptosis, differentiation increased the susceptibility of SK-N-BE cells to detachment-induced apoptosis. The appearance of the apoptotic-like phenotype required the maintenance in suspension of SK-N-BE cells for at least 16 h (12.43 ± 1.40% of cells undergoing apoptosis) and the percentage increased up to 46.84 ± 3.15% after 24 h. Suspension-induced apoptosis did not depend on increased intracellular Ca2+levels nor onde novoprotein synthesis and was not associated with extensive DNA degradation. Stimulation by soluble collagen I rescued suspended cells from apoptosis, even in the absence of cell adhesion and spreading. The survival promoting effect of ECM was mediated by the integrin receptors, since ([1]) the protective effect of soluble collagen I was blocked by anti-integrin antibodies to β1and α1subunits and ([2]) the antibody-induced clustering of α1, α3, αv, β1, and β3integrins rescued SK-N-BE cells cultured in suspension from apoptosis. As expected, adhesion on immobilized ECM proteins, collagen I, or laminin (0.1 to 10 μg/ml) also rescued SK-N-BE cells from apoptosis in a dose-dependent manner. Thede novoprotein synthesis was required to promote the survival effect of ECM, since cycloheximide completely abolished the protective effect of collagen I and protection from apoptosis by ECM or by anti-β1antibody was associated with the increased expression ofbcl-2.In addition to integrin stimulation, serum, insulin, and nerve growth factor inhibited suspension-induced apoptosis of SK-N-BE cells. The survival effect of serum and growth factors did not require the synthesis of new proteins, unlike the ECM effect. These data show that matrix proteins can promote cell survival in neuronal cells via integrin receptors. This effect does not require cell adhesion and the subsequent changes in cell shape as it can be mediated by soluble integrin ligands in suspended cells and involves a signaling pathway different from that triggered by growth factors. 相似文献
19.
Although the existence of an increasing number of angiogenesis-regulating cytokines is well documented, the response elicited by combinations of these cytokines is largely unknown. Using an in vitro model in which microvascular endothelial cells can be induced to form capillary-like tubes within three-dimensional collagen or fibrin gels, we have investigated the effect of transforming growth factor-β1 (TGF-β1) on basic fibroblast growth factor (bFGF)-induced and vascular endothelial growth factor (VEGF)-induced angiogenesis. Endothelial cell invasion and capillary lumen formation were inhibited by TGF-β1 at relatively high concentrations (5-10 ng/ml), while lower concentrations (100 pg/ml-1 ng/ml) of TGF-β1 potentiated the effect of bFGF- and VEGF-induced invasion. The optimal potentiating effect was observed at 200-500 pg/ml TGF-β1. At invasion-potentiating doses of TGF-beta;1, lumen size in fibrin gels was markedly reduced compared to that in cultures treated with bFGF alone. These results show that TGF-β1 exerts a biphasic effect on bFGF- and VEGF-induced angiogenesis in vitro. Our studies support the notion that the nature of the angiogenic response elicited by a specific cytokine is contextual, i.e., depends on the presence and concentration of other cytokines in the pericellular environment of the responding endothelial cell. 相似文献
20.
Helga Joos Anja Wildner Cathrin Hogrefe Heiko Reichel Rolf E Brenner 《Arthritis research & therapy》2013,15(5):R119